Mix and match these protein-rich sources to score 20 to 30 g at each meal

New research suggests that many of us may need more protein than we realize. The current RDA is 0.8 g of protein per kilogram of body weight, but several studies have found that 1 to 1.2 g may be more protective against age-related muscle loss.

Use this formula from Caroline Apovian, MD, to determine the minimum amount of protein you should eat daily to offset muscle loss—and protect your metabolism—while you lose weight.

STEP 1Estimate your ideal weight. "If you're a woman, start with 100 pounds for the first 5 feet in height, and add 5 pounds for every extra inch," says Dr. Apovian. "For men, it's 106 pounds for 5 feet in height, plus 6 pounds for every additional inch. However, if your ideal weight is less than 120 pounds, don't eat less than 82 g of protein daily."

STEP 2Ideal Weight (in lb) ÷ 2.2 = Ideal Weight (in kg)

STEP 3Ideal Weight (in kg) × 1.5 = Daily Protein Goal (in g)

Now that you know how much you need, check out these metabolism-boosting protein-packed foods.